The unbelievable strength of this rally is why so many traders are absolutely convinced that there must be manipulation going on, whether it's the government's plunge-protection team or Goldman Sachs (GS).

Whatever it is, after languishing through much of the day, stocks soared in the final minutes out of nowhere, signalling a healthy thirst for stocks ahead of the weekend.

The S&P 500 finished up 3.6% for the week, while the Dow managed to end the week just above 8500.